The present invention relates to convection-heated conveyor ovens and airflow components for such ovens.
Convection-heated conveyor ovens, examples of which are shown in U.S. Pat. Nos. 5,277,105, 6,481,433, 6,655,373, and 8,087,407 (each of which is incorporated herein by reference), may be used to cook a variety of food products, such as bread or pizza, among other products. Food is cooked by blowing heated air onto the food product to be cooked from above and below a conveyor belt on which the food is carried. Larger or smaller blowers may be used depending on the size of the oven. While smaller blowers offer a finer degree of control and higher efficiency, they are less practical for larger ovens.
Conveyor ovens are typically large metallic housings with a heated tunnel extending through them and a conveyor running through the tunnel. Conveyor ovens may be constructed in any suitable size. The conveyor transports food products through the heated oven tunnel at a speed which bakes food products during their transit through the tunnel. Such conveyor ovens typically include a heat delivery system including blowers which supply heated air to the tunnel from a plenum which is heated by one or more gas burners or other heating elements. The blowers force the heated air through passageways leading to metal fingers that open into the oven tunnel at locations above and below the conveyor. The metal fingers act as airflow channels that deliver streams of hot air which impinge upon the surfaces of the food products passing through the tunnel on the conveyor. In modern conveyor ovens, a microprocessor-driven control panel generally enables the user to regulate the heat, the speed of the conveyor, etc., to properly bake the food product being transported through the oven. A food product, such as a raw pizza, may be placed on the conveyor at one end of an oven and removed from the conveyor as a fully baked pizza at the other end of the oven. The speed at which the conveyor moves is coordinated with the temperature in the heated tunnel so that the emerging fully cooked food is properly baked or cooked.
Heat delivery systems for conveyor oven systems typically include a heat source in the form of one or more gas-fired burners (or other heat source) for heating a plenum. For example, the burner can be located at the front or back of the oven for heating a plenum located at the back of the oven. Blowers are typically provided to move heated air in the plenum through passageways to metal fingers that open into the oven at appropriate spacings from the conveyor belt to deliver streams of hot air onto food products being transported on the conveyor. The heat source is cycled on and off as necessary by a controller responding to signals from temperature sensors (e.g., thermocouples) positioned, for example, at the inlet and outlet ends of the oven tunnel.